Seat suspension



Dec. 31, 1963 D. H. BANZHAF SEAT SUSPENSION Filed March 2l, 1962INVENTOR. DONALD H. BANZHAF AT-roRm-:Y

United States Patent Oliice mg Patented Dec. 31, 1963 3,116,089 SEATSUSPENSION Donald H. Banzhaf, Brookfield, Wis., assigner to Harley-Davidson Motor Co., Milwaukee, Wis., a corporation of Wisconsin FiledMar. 21, 1962, Ser. No. 181,285 14 Claims. (Cl. 297-203) This inventionrelates to seat suspension mechanisms and, more particularly, to seatsuspensions of the type used in motorcycles or like vehicles.

Heretofore, such suspensions have included a primary spring usuallylocated in the center seat post and having a spring rate suflicient toaccommodate one rider. To accommodate two riders, auxiliary springs wereprovided which could be selectively connected to increase the springrate of the suspension and make it compatible with the load of tworiders. In accordance with commonly accepted practice, the auxiliarysprings were exteriorly located thereby being susceptible to damage andalso detracting generally from the overall appearance of the vehicle.

An object of this invention is to provide a compact and integrallyarranged seat suspension which is readily adjustable to accommodate oneor two riders.

Another object is to provide an enclosed seat suspension which isreadily adjustable to accommodate different seat loads.

Another consideration in such seat suspensions is what is known as seatrebound. When the seat is moved down against the spring force, thesprings tend to snap the seat back to its normal position with nodamping other than the hysteresis loss of the spring system.

Accordingly, another object of this invention is to provide a seatsuspension which resists this rebounding force while maintaining thecompact and enclosed nature of the suspension.

For the achievement of these objects this invention contemplates theprovision of a compact and integrally Varranged seat suspensionmechanism which biases the seat toward a normal position and opposesmovement of the seat in response to a load applied thereto, thesuspension mechanism being selectively adjustable to oppose that seatmovement with either of two forces so that the seat is equally suitedfor use with different loads, i.e. one or two riders. rPhe suspensionmechanism is so arranged that it can be accommodated within a hollowenclosure such as the center frame post of a motorcycle frame and alsoincludes a mechanism which is operative to offer little or no resistanceto movement of the seat away from the normal position but which retardsreturn movement of the seat to its normal position.

The novel features of this invention are set forth in the appendedclaims. The invention itself, together with additional objects andadvantages thereof, will be more clearly understood from a reading ofthe following description in connection with the accompanying drawingswherein a preferred embodiment of this invention is illustrated and inwhich:

FIG. 1 is a side elevation of a seat and a portion of its suspensionmechanism;

FIG. 2 is a view along lines 2 2 of FIG. l;

FG. 3 is a sectional view along lines 3 3 of FIG. 2;

FIG. 4 is a sectional View along lines 4 4 of FIG. 3 showing the seatplunger as positioned for only one rider;

FIG. 5 is similar to FIG. 4 showing the seat plunger as positioned fortwo riders; and

FIG. 6 is a sectional view along lines 6 6 of FIG. 5.

With particular reference to the drawings, seat 10 is illustrated as itwould be mounted on a vehicle such as a motorcycle. The seat isconnected at its front end to chassis 12 by hinge i4 and carries bracket16 from which a seat post plunger 18 is hingedly suspended. Plunger 18extends into the vehicle frame center post 20 which houses the seatsuspension.

Referring to FIG. 3, retaining ring 22 is carried by plunger l and ispositioned intermediate inner and outer springs 24 and 26. Washers 28and 3@ are disposed on either side of retaining ring Z2. Washer 28engages one end of spring 24 which is then seated between that washerand an insert 32 welded in the bottom of center post 20. Washer 36engages a floating bushing 34 which normally rests on shoulder 36provided in center post 20. Spring 26 is seated between floating bushing34 and a floating bushing 38 which rests atop spring 26 and is preventedfrom moving out of the center post by a retaining ring 4t) fixed to thetop of the center post by bolts ll-41.

Preferably, when installed, spring 26 exerts a greater force than spring24, so that bushing 34 is normally maintained in engagement withshoulder 36 and acts as a stop to limit the upward travel of retainingring 22, and correspondingly the plunger and the seat, under theiniluence of spring 24. This also establishes a normal, unloadedposition for the plunger wherein a spring rate adjusting mechanism 42 isheld within the center post in an inoperative condition. In this normalposition the seat is supported to accommodate one rider with only spring24 opposing downward movement of the plunger, and the seat, as a resultof a deilecting load applied to the seat. It should also be noted that,although spring 26 is not connected to the plunger to oppose downwardmovement of the seat, it does resist upward movement of the plunger andthereby opposes seat movement in that direction. Therefore, thesuspension is in effect a double acting suspension system.

Spring rate adjusting mechanism 42 is disposed in diametrical opening 44in plunger 18. Pins 46 and 43 are positioned in opening 44 with pin 48engaging an annular shoulder 50. A retaining ring S2 is press fitted andstaked into opening 44 and spring 54 biases the pins outwardly.

As can be seen in FIGS. 4 and 5, with the plunger in its normal positionmechanism 42 is positioned within the post in an inoperative position soas not to interfere with motion of the plunger. More particularly,spring 26, exerting a greater force than spring 24, holds bushing 34 inengagement with shoulder 36 thereby limiting the upward travel ofretaining ring 22 under the inuence of spring 24 and maintainingadjusting mechanism 4Z inoperative within the bore of bushing 3S. Toadjust the seat suspension to accommodate two riders, the seat is raisedmanually and plunger 18 withdrawn from the center post an amountsuicient to free mechanism 42 and allow pins 46 and 48 to move outwardlyof the plunger under the influence of spring 54 (see FIGS. 5 and 6).Retaining ring 4t) is provided with opening 56 so that when released theseat pins 46 and 43 clear ring 4t) and engage a washer 58 which,together with a felt wiper 6), rests atop floating bushing 38. Theoutward movement of plunger 18 to release mechanism 42 also raisesbushing 34 from shoulder 36 and compresses spring 26. After mechanism 42and the seat have been released and pins 46 and 4S engaged with washer58, bushing 34 will return to engagement with shoulder 36. Bushing 38 isnow coupled with the plunger for joint movement therewith relative tothe center post. A force tending to move the seat downward will now beresisted by both springs giving the suspension an increased spring ratesufficient to accommodate two riders. The suspension is readilyconverted back to accommodate one rider by merely depressing the pinsand allowing the plunger to be drawn into the center post by the springsand returned to its normal position with mechanism 42 disposed withinbushing 3S and inoperative.

To cushion the impact and shock when plunger 18 3 is bottomed, aresilient neoprene cushion 62 is connected to insert 32 by a stud 64.The Stud is held in fixed relation with the insert by nut 66 and washers65 and 7 0.

Suspension systems of this type are susceptible to what is known as seatrebound, i.e. after the plunger and the seat have been moved downwardlydeecting the springs, the springs tend to snap the seat upwardly to itsnormal position which can create a quite uncomfortable condition for therider or riders. To alleviate seat rebound, the seat suspension isprovided with a shock absorber or rebound retarder. More particularly,the lower portion of center post 2b is lled with oil or other suitableuid to a level 72. Stud 64 extends through a plug 74 connected in thebottom of plunger 18 and into the plunger. A flexible cup-shaped member78 is supported on the upper end of stud 64. Oil iills the interior oiplunger ld' through openings 8l) in the plunger and orifices 82 providedin plug 74. Member 73 acts in the nature of a one way valve in that, asplunger 18 moves downwardly, a partial vacuum is created between it andplug 74 and member 73 collapses allowing oil to ll the spacetherebetween. However, as the plunger is forced upwardly by the springs,member '78 is pressed against the inner walls of plunger i8 preventingthe escape of oil. The oil trapped between members '7S must pass throughthe restricted orifices 82 thereby retarding upward motion of theplunger and alleviating the problem of seat rebound.

The discussion and illustration of this invention in relation to aparticular preferred embodiment thereof has been intended forillustrative purposes only and should not be taken by way of limitation.Accordingly, it is intended in the appended claims to cover allmodiiications and embodiments of this invention as tall within the truespirit and scope thereof.

What I claim is:

l. A suspension mechanism for use in combination with a vehicle seatmounted for movement relative to a vehicle, said suspension mechanismcomprising, a hollow enclosure, a pair of resilient members positionedwithin said hollow enclosure, and means for connecting one of saidresilient members to continuously oppose movement of said seat when adellecting load is applied thereto and for selectively connecting theother of said resilient members to cooperate with said one resilientmember in opposing7 said seat movement.

2. The combination of claim 1 including shock ablsorber means disposedWithin said hollow enclosure and operative to retard rebound of saidseat subsequent to said movement of said seat.

3. A suspension mechanism for use in combination with a vehicle seat andcomprising, in combination, a hollow enclosure, a rigid member extendinginto said hollow enclosure and being connected to said seat for movementtherewith, a pair of springs disposed within said hollow enclosure andengageable with said rigid member, means for guiding said rigid memberfor movement against the bias of said springs when a deilecting load isapplied to said seat, and means for connecting one of said springs tocontinuously oppose said movement of said rigid member by saiddeilecting load and for selectively connecting the other of said springsto cooperate with said one spring in opposing said movement of saidrigid member.

4. The combination of claim 3 including shock absorber means disposedwithin said hollow enclosure and operative to retard rebound of saidseat subsequent to said movement of said rigid member.

5. A suspension mechanism for use in combination with a vehicle seatmounted for movement relative to a vehicle, a rigid member connected toand movable with said seat, a pair of coaxially arranged springspositioned with their lines of action extending parallel to thedirection of movement of said rigid member, and means for connecting oneof said springs to continuously oppose V:movement of said rigid memberwhen a deflecting load is `springs disposed within said hollow enclosureand surrounding said elongated member, means carried by said elongatedmember and arranged intermediate said springs for engagement with eachof said springs, said inner i yspring seated between said means on saidelongated .member and the inner end of said hollow enclosure, Vmeans forseating said outer spring at spaced apart points along said hollowenclosure and limiting the inward movement of said outer spring, saidsprings biasing g :said rigid member and said seat toward a normalposition, and means for selectively connecting said outer spring to saidelongated member to oppose motion of :said elongated member away fromsaid normal position when a deflecting load is applied to said seat,said conecting means operative when said elongated member is iin saidnormal position to provide relative movement between said rioid memberand said outer spring.

8. The combination of claim 7 and wherein the seating .means for saidouter spring includes a stop member engaging the inner end of said outerspring and also said hollow enclosure to limit the inward move- Inent ofsaid outer spring, said stop member also engaging said means carried onsaid elongated member and -:said outer spring exerting a greater forcethan said inner spring.

9. The combination of claim 7 wherein said selective connecting means iscarried by said elongated member .and comprises at least one membermovable transversely with respect to said elongated member and biasedtoward a normal position extending laterally of said elongated member,said transversely movable member being disposed within said elongatedmember when said elongated member is in its normal position and beingreleased upon movement of said elongated member outwardly of said hollowenclosure for engagement with said outer spring so that said outerspring is connected to cooperate with said inner spring in opposingmovement oi said seat when a deecting load is applied to said seat.

10. The combination of claim 7 including shock absorber means disposedwithin said hollow enclosure and operative to retard rebound of saidseat subsequent to said movement of said seat away from said normalposition.

1l. The combination of claim 7 wherein said elongated member has ahollow portion at its inner end and further includes a llexible memberdisposed within said hollow portion of said elongated member, a duidmedium within said hollow enclosure, means for admitting said fluid tothe interior or said elongated member, means providing a restrictedorice at the inner end of said elongated member, and means connectingsaid flexible member for movement of said elongated member relativethereto and arranging said llexible member so that upon movement of saidelongated member when a deflecting load is applied to said seat saidduid medium flows freely past said llexible member and upon returnmovement oic said elongated member said lexible member obstructs iluidlow causing the iluid to be expelled through said restricted oriiice.

12. The combination of claim 11 wherein said flexible member iscup-shaped and opens toward said inner end of said elongated member.

13. A suspension mechanism for use in combination with a vehicle seatand comprising, in combination, an

d hollow enclosure, an clone-ded nernber extending ino said hollowenclosure and being,7 eonneeed o eea for movement therewith, inner andouer Coil springs disposed Wiliin said hollow enclosure and surroundingelongaed member, means carried by said eongeied n1- oer ^ncl erro edimerinedae said springs for conne on with eaen of said springs, saidinner spring seated beween seid rneans on said elongaied member and lieinner en -l of said hollow enclosure, e slop mernier positioned abovesaid means carried by said elongoed inernber lovable willin saidenclosure, means lining movemen of said sop member inwardly of saidhollow enclosure, l'ie inner end of sai-:1 outer s; ing eonneeied Vtosaid sop member and a. second seaing member nionned for movement Wiliinsaid enclosure and eonneeed o ille opposiie end of said oner spring, liithe oulward movemen of said seaing member whereby said springs bias saidrigid rneinber and said seat toward a normal position, and meansselectively conneeable beween said Second ine'noer and said elongaedmember to conne/ said second member and said elongated rnernber for joinmovement in response ro a deflecing load on said seat and o selectivelydisconnect said second member and said oiongated member for relativemovement therebeween so *Snai movmen of said vehicle seat from saidnormal posiion under the influence of a load is coninuously opposed byseid inner spring and seeeively opposed by a combinaion of said innerspring and said eurer spring.

14. The eombinaion of claim 13 wherein said second member includes abore Wil said elongated member being,r disposed for niovernen wiliinsai-:1 bore and Wherein said selee'riveiy eonneeaoie means comprises atleast one member moveibie ransversely of and biased toward a normal po-on extending laereily o said elongaed rneinber, said transverselyrnovabie member disposed wieA in bore when said elongaed member is inits normal position and being released upon movement o' said elongaedmember ouwardly o said bellow enclosure for eonneeion Wih tbe outer endof the second member io connee; seid second spring for coopera- Lionwith said inner spring in opposing movement of said seal; :han adefieeing load is applied liereo.

References Ci'e in the iile of this paen UNITED STATES PATENTS

1. A SUSPENSION MECHANISM FOR USE IN COMBINATION WITH A VEHICLE SEATMOUNTED FOR MOVEMENT RELATIVE TO A VEHICLE, SAID SUSPENSION MECHANISMCOMPRISING, A HOLLOW ENCLOSURE, A PAIR OF RESILIENT MEMBERS POSITIONEDWITHIN SAID HOLLOW ENCLOSURE, AND MEANS FOR CONNECTING ONE OF SAIDRESILIENT MEMBERS TO CONTINUOUSLY OPPOSE MOVEMENT OF SAID SEAT WHEN ADEFLECTING LOAD IS APPLIED THERETO AND FOR SELECTIVELY CONNECTING THEOTHER OF SAID RESILIENT MEMBERS TO COOPERATE WITH SAID ONE RESILIENTMEMBER IN OPPOSING SAID SEAT MOVEMENT.